"People tell us that they are beaten, made to lie on the ground while police officers stomp on them wearing boots," said Christopher Stokes, MSF General Director, who visited refugees in Serbia.

"They add that their clothes and shoes are often confiscated in the snow so that they have to walk back to Serbia barefoot through the cold."

He said refugees bore tell-tale signs of attacks by border guards and stories of humiliation were frequent.

Stokes said EU leaders were turning a "blind eye" to these abuses and called on them to take action. He said the injuries the "tip of the iceburg" and many refugees don't come forward when hurt.

The news comes as Hungary ramped up its anti-migrant policies with a wall being built on its borders with Balkan countries to prevent refugees entering.

Hungary has been accused of "making a mockery" out of the right to asylum by Human Rights Watch, after the government said it sought new powers for police to round up migrants anywhere in the country and transfer them to the Serbia border.

Hungary's "border hunters" have a fearsome reputation with a recruitment drive by the government to attract 3,000 guards to the force and trained in martial arts and the ability to break "break resistance".